(a) Field of the Invention
The present invention relates to an Ethernet apparatus and a method of adjusting a transmission rate thereof. Particularly, the present invention relates to an Ethernet apparatus having a multiple lane structure and a method of adjusting a transmission rate of the Ethernet apparatus.
(b) Description of the Related Art
As the number of apparatuses that are connected to a data network increases and a high data transmission ratio is required, new transmission techniques that can transmit data at a high speed are necessary.
As a data transmission speed increases, power consumption of a communication apparatus greatly increases. Accordingly, when communicating data in an Ethernet interface of a high speed, a method of reducing power consumption includes a rapid PHY selection (RPS) method and a low power idle (LPI) method.
The RPS method is embodied using a physical layer (PHY) module having a transmission rate of a high speed and a PHY module having a transmission rate of a low speed. The RPS method operates by selecting a PHY module that supports a transmission rate of a high speed when the amount of data to transmit is large, and operates by selecting a PHY module of a low speed using low power when the amount of data to transmit is less.
That is, in the RPS method, a PHY module that can be independently operated according to a supporting transmission rate should be embodied, and in order to perform transmission rate conversion between different PHY modules, a protocol for an agreement between two apparatuses that are positioned at both ends of a link should be performed. However, in the RPS method, in a transition process between different PHY modules, there is a problem that a time period in which data cannot be transmitted using a link exists.
The LPI method transmits with a maximum transmission rate in which a link supports transmission when data to transmit exists, and operates a link in an idle state when data to transmit does not exist.
The LPI method can reduce power consumption by sustaining some of circuits requiring for transmitting/receiving data in an inactive state when data to transmit does not exist. Further, the LPI method sustains state information for allowing a link to operate again in a transmission active state by periodically transmitting a control signal in a period of sustaining a link in an idle state.
However, the LPI method can effectively reduce energy when transmitting traffic having strong burst characteristics, but has a problem that it cannot reduce energy when transmitting traffic of a streaming form requiring a continuous transmission service with a low data rate.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.